1. Field of the Invention
The present invention relates to a conveyance-direction switching device in a roller conveyor that conveys objects in a certain direction by means of rotationally driven drive rollers including those with built-in motors, capable of shifting the carried objects transversely with respect to the roller conveyor.
2. Prior Art
A device for switching the conveyance directions of objects to be carried on a roller conveyor is necessary for sorting objects, etc. at distribution centers, etc. Commonly used methods for switching conveyance directions include those arranging two conveyors in a fork (in the shape of Y) and using a diverging device to switch the conveyance directions, as well as those employing a pusher that intersects with the conveyance direction to forcibly divert certain objects transversely.
All of these conventional conveyance-direction switching devices require a separate driving means for switching the conveyance direction. Accordingly, such conveyance-direction switching devices are generally complicated and expensive and are not easily installed in an existing conveyor device.
The object of the present invention is to overcome the disadvantages of such conventional techniques and to provide a simple structured conveyance-direction switching device used in a roller conveyor that requires no special driving means.
In order to achieve the objects of the present invention, below a rotationally driven drive roller, transverse rollers having rotation axes that intersect wit the rotationally driven drive roller so that the transverse rollers are raised and lowered freely are provided. When the transverse rollers are in the raised position, they come into partial contact with the drive roller and are rotated. At this time, the uppermost edges of the transverse rollers project above the uppermost edge of we chive roller. With this arrangement, the torque of the drive rolls is transmitted to the transverse rollers, and the objects that are conveyed are diverted transversely by the torque of the drive roller.
Transmission of the torque of the drive roller to the transverse rollers can be achieved by arranging the rotation axes of the drive roller and transverse rollers in such a way that they intersect with each other at an angle other than right angles. With this arrangement, some portions of the drive roller come into contact with some points on the peripheral surfaces of the transverse rollers. The frictional forces at these contact points rotationally drive the transverse rollers.
In order to allow the transverse rollers to divert the objects carried by the drive rollers in an orthogonal direction, auxiliary rollers are used. Each auxiliary roller is paired with a transverse roller and is arranged so as to make contact with the radial side of the end face, preferably near the periphery, of the transverse roller. In this structure, the transverse rollers are arranged in the direction that intersects with the drive roller at right angles. The transverse rollers are raised and lowered; and when they are in the raised position, the auxiliary rollers come into contact with the drive roller. In this way, the torque of the drive roller is transmitted to the auxiliary rollers, and the torque of the auxiliary rollers is transmitted to the transverse rollers.
Preferably, the transverse rollers are provided at several positions along the drive roller in order to achieve smooth transverse diversion. It is also preferable that several drive rollers are equipped with transverse rollers, forming a transverse conveyor having a certain width. So as to realize such a conveyance-direction switching device equipped with many transverse rollers, transverse rollers are provided at several positions in a lift, and the lift is raised and lowered so that the transverse rollers provided at the several positions come into contact with different drive rollers and are rotated by the drive rollers.